The audit said the Department of Human Services shouldn't have licensed or registered about 1,900 day work providers.

The audit said background checks done by the state weren't effective in identifying perpetrators of child abuse or neglect, sex offenders and others.

State officials agreed with the audit's recommendations. They said in the audit report that in April 2007, they began running additional background checks after being informed a main background check program wasn't flagging enough offenders.

A message seeking comment was left Tuesday morning with a DHS spokesman.

Between October 2003 and March 2006, the state licensed or registered 116,585 day care providers to care for 273,364 children whose lower-income families get financial assistance for day care. About 4,600 of those children were put at risk, according to the audit.

Auditors said they flagged 1,900 day care providers because they were substantiated child abusers or neglecters, had unsuitable criminal histories, were sex offenders, had been convicted of other serious crimes or were incarcerated in prison or under parole restrictions limiting their contact with children.

The audit criticized the state for using only Social Security numbers to match against offender registries and not other information such as names and dates of birth.